Typically, undo and redo are represented by curved or rounded arrows. They are correct in MarginNote as shown:
However in research mode the back/forward navigation arrows are also rendered as curved arrows:
Curved arrows are used to represent undo/redo in most applications and in research mode the back and forward arrows look like undo and redo. Browsers, however, use a straight arrow with no curves to represent back and forward navigation. Firefox, Chrome, and Safari are shown below.
This is a small issue but one that I do a double-take on every time I look at those back and forward navigation arrows in research mode. Please follow standard UX principles regarding the shape of these icons and straighten them out.